Multilayer fluorescent optical fiber temperature measurement system and application method thereof

Abstract

The invention relates to the technical field of fluorescent optical fiber temperature measurement devices, in particular to a multi-layer fluorescent optical fiber temperature measurement system and an application method thereof.The multi-layer fluorescent optical fiber temperature measurement system comprises a connector, an optical fiber sensor and a photoelectric signal processing device, and the connector is connected to the interior of a ring main unit through a cable; the optical fiber sensor is arranged in the ring main unit, one end of the optical fiber sensor is a probe end, the other end of the optical fiber sensor is an optical fiber end, and the optical fiber sensor is connected with the connector through the probe end; the photoelectric signal processing device is arranged in the ring main unit, and the photoelectric signal processing device is connected with the optical fiber end of the optical fiber sensor. The device has the characteristics of electromagnetic interference resistance, miniaturization and high precision, and high-precision temperature monitoring in the ring main unit of the power system is realized through the design of multiple layers of fluorescent materials and multiple optical fiber probes and an improved signal processing algorithm.

Description

Technical Field

[0001] This invention relates to the field of fluorescent fiber optic temperature sensing devices, and more specifically, to a multilayer fluorescent fiber optic temperature sensing system and its application method. Background Technology

[0002] Ring main units are commonly used medium-voltage power distribution equipment in urban power distribution systems. Their internal cable joints, busbars and other components are prone to high temperatures during operation due to current load. If not monitored in time, this may lead to insulation aging or failure.

[0003] Traditional temperature measurement systems suffer from insufficient shielding, making them susceptible to high electromagnetic interference within ring main units, resulting in large measurement errors. Furthermore, the high power consumption of these systems makes them unsuitable for continuous online monitoring. The limited space within ring main units, coupled with the large size of traditional sensors, further complicates installation.

[0004] Existing fluorescent fiber optic temperature measurement technology uses a single fiber optic probe, which has low signal collection efficiency. A single fluorescent material cannot cover the wide temperature range of cable joints and busbars, and the fluorescence intensity decays severely under high temperature conditions. The temperature measurement lifespan stability is insufficient, making it difficult to meet the accuracy requirements of ring main unit temperature measurement.

[0005] Traditional signal processing algorithms are sensitive to noise, have difficulty processing complex fluorescence decay curves, and have long response times, which cannot meet the requirements of real-time monitoring. Summary of the Invention

[0006] The purpose of this invention is to provide a multilayer fluorescent fiber optic temperature measurement system and its application method to improve the aforementioned problems. To achieve this purpose, the technical solution adopted by this invention is as follows:

[0007] In a first aspect, this application provides a multilayer fluorescent fiber optic temperature measurement system, comprising: a connector, a fiber optic sensor, and a photoelectric signal processing device. The connector is connected to the inside of a ring main unit via a cable. The fiber optic sensor is placed inside the ring main unit, with one end of the fiber optic sensor configured as a probe end and the other end configured as a fiber optic end. The fiber optic sensor is connected to the connector via the probe end. The photoelectric signal processing device is disposed inside the ring main unit and is connected to the fiber optic end of the fiber optic sensor.

[0008] Preferably, the probe end of the fiber optic sensor is provided with a fluorescent layer and an encapsulation layer, the outer surface of the probe end is coated with the fluorescent layer, and the encapsulation layer is sleeved on the fluorescent layer.

[0009] Preferably, the optical fiber end of the optical fiber sensor includes a transmission optical fiber, a fiber material, and a first protective layer. The transmission optical fiber is wrapped with the fiber material, the first protective layer is sleeved on the fiber material, and one end of the transmission optical fiber is connected to the probe end.

[0010] Preferably, the fluorescent layer is configured as a double layer, the first fluorescent layer is configured as a fluorescent layer containing Y2O3:Eu, wherein the component ratio of Y2O3:Eu to phosphor is 1.5:1, the second fluorescent layer is configured as a fluorescent layer containing YPO4:Tb, wherein the component ratio of YPO4:Tb to phosphor is 1.5:1, the coating thickness ratio of the first fluorescent layer to the second fluorescent layer is 1.5:1, and the second fluorescent layer is disposed between the first fluorescent layer and the encapsulation layer.

[0011] Preferably, the transmission optical fiber is composed of one excitation optical fiber and six collection optical fibers. The six collection optical fibers are arranged around the excitation optical fiber, and the excitation optical fiber is located in the center of the six collection optical fibers. The optical fibers are arranged at a 25° angle to each other.

[0012] Preferably, the photoelectric signal processing device includes a light source module, a signal processing module, and a data output module. The light source module is positioned facing the collecting optical fiber and emits an optical signal into the collecting optical fiber. The signal processing module is positioned facing the excitation optical fiber and receives a fluorescence signal emitted by the excitation optical fiber. The signal processing module is electrically connected to the data output module.

[0013] Preferably, the light source module is configured as a dual-wavelength LED light source, with wavelengths set to 470nm and 532nm respectively, and a pulse modulation frequency of 15kHz.

[0014] Preferably, the signal processing module includes a high-speed silicon photodiode and an embedded DSP processor. The high-speed silicon photodiode is positioned facing the excitation fiber. The high-speed silicon photodiode receives the fluorescence signal emitted by the excitation fiber and converts the fluorescence signal into an electrical signal. The high-speed silicon photodiode is electrically connected to the embedded DSP processor and transmits the electrical signal to the embedded DSP processor.

[0015] Preferably, the fiber optic sensor is covered with a second protective layer, which is made of high-temperature resistant ceramic and has an outer diameter of 0.25 mm.

[0016] Secondly, this application also provides an application method for a multilayer fluorescent fiber optic temperature measurement system, including:

[0017] Connect the connector to the inside of the ring main unit via a cable;

[0018] Make the probe end of the fiber optic sensor directly contact or be close to the temperature measuring point on the connector;

[0019] The light source module in the photoelectric signal processing device emits an LED light source to the optical fiber end of the optical fiber sensor with a pulse modulation frequency of 15kHz, and the light signal is collected by the six collecting optical fibers to the fluorescent layer at the probe end of the optical fiber sensor.

[0020] The probe end of the fiber optic sensor integrates a miniature beam splitter, which separates the signal through wavelength selective excitation, radiates fluorescence to form afterglow, and excites the signal processing module in the photoelectric signal processing device through the excitation fiber and the afterglow.

[0021] The high-speed silicon photodiode in the signal processing module, in conjunction with the low-noise preamplifier circuit, acquires the fluorescence signal and converts it into an electrical signal. The circuit is set to a bandwidth of 120kHz.

[0022] The embedded DSP processor in the signal processing module integrates the adaptive Prony algorithm, and through dynamic baseline correction and multi-band noise filtering, fits the double exponential decay curve of the multilayer fluorescent material to calculate the measured temperature.

[0023] The measured temperature is output through the data output module.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention employs a multi-layer fluorescent material design, achieving a wide temperature range measurement of 0-200℃ through wavelength-selective excitation and signal separation, with a temperature measurement accuracy improved to ±0.2℃. Compared to traditional fluorescent fiber optic temperature measurement systems, this represents an 80% improvement in accuracy, effectively meeting the high-precision temperature monitoring requirements of ring main units. The small-diameter multi-fiber reflective sensor, through optimized angle arrangement and anti-electromagnetic interference coating, improves signal collection efficiency by 25%, achieves a background light suppression rate exceeding 95%, and perfectly adapts to confined spaces such as cable joints and busbars in ring main units, maintaining signal stability even under high voltage and strong electromagnetic interference environments.

[0026] This invention employs an improved adaptive Prony algorithm, which enhances noise immunity by 30% through dynamic baseline correction and multi-band noise filtering. Its processing speed is 50% faster than traditional algorithms, and the response time is reduced to 0.004ms, fully meeting the stringent requirements of real-time online monitoring of ring main units. The overall system power consumption is less than 0.8W, and the use of high-efficiency dual-wavelength LED light sources and high-speed silicon photodiodes ensures low thermal effects and high stability during long-term system operation.

[0027] After actual testing, in scenarios involving 10kV ring main unit cable joints (50-150℃) and 35kV busbars (100-200℃), the system temperature measurement error remained within ±0.2℃, and the fluorescence signal intensity attenuation rate was less than 3%. This significantly improved the reliability and service life of the ring main unit temperature monitoring equipment, enhanced the efficiency of temperature measurement, and provided strong technical support for the safe operation of the power system.

[0028] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the fiber optic sensor structure of a multilayer fluorescent fiber optic temperature measurement system according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the transmission fiber arrangement of a multilayer fluorescent fiber optic temperature measurement system according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the connection relationship of a multilayer fluorescent fiber optic temperature measurement system according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the insertion installation of the fiber optic sensor described in an embodiment of the present invention;

[0034] Figure 5 This is a simplified installation diagram of the fiber optic sensor described in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the embedded installation of the fiber optic sensor described in an embodiment of the present invention.

[0036] The markings in the diagram are: 1. Connector; 2. Transmission fiber; 21. Excitation fiber; 22. Collection fiber; 3. Fluorescent layer; 4. Encapsulation layer; 5. Fiber material; 6. First protective layer; 7. Second protective layer; 8. Temperature measuring point; 9. Embedded connector. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] Example 1:

[0040] like Figures 1 to 3 As shown, this embodiment provides a multilayer fluorescent fiber optic temperature measurement system, including: a connector 1, a fiber optic sensor, and a photoelectric signal processing device. The connector 1 is connected to the inside of a ring main unit via a cable. The fiber optic sensor is placed inside the ring main unit, with one end of the fiber optic sensor configured as a probe end and the other end configured as a fiber optic end. The fiber optic sensor is connected to the connector 1 through the probe end. The photoelectric signal processing device is located inside the ring main unit and is connected to the fiber optic end of the fiber optic sensor.

[0041] like Figure 1 and Figure 2 As shown, the probe end of the fiber optic sensor is provided with a fluorescent layer 3 and an encapsulation layer 4. The outer surface of the probe end is coated with the fluorescent layer 3, and the encapsulation layer 4 is sleeved on the fluorescent layer 3. The fiber end of the fiber optic sensor includes a transmission fiber 2, a fiber material 5, and a first protective layer 6. The transmission fiber 2 is wrapped with the fiber material 5, and the first protective layer 6 is sleeved on the fiber material 5. One end of the transmission fiber 2 is connected to the probe end. The transmission fiber 2 is composed of one excitation fiber 21 and six collection fibers 22. The six collection fibers 22 are arranged around the excitation fiber 21, and the excitation fiber 21 is located in the center of the six collection fibers 22. The fibers are arranged at a 25° angle. The multi-fiber reflective sensor improves the signal collection efficiency by 25% by optimizing the angle arrangement.

[0042] like Figure 3 As shown, the photoelectric signal processing device includes a light source module, a signal processing module, and a data output module. The light source module is positioned facing the collecting optical fiber 22 and emits an optical signal into the collecting optical fiber 22. The signal processing module is positioned facing the excitation optical fiber 21 and receives the fluorescence signal emitted by the excitation optical fiber 21. The signal processing module is electrically connected to the data output module.

[0043] This invention connects the connector 1 to the inside of a ring main unit via a cable, allowing the probe end of the fiber optic sensor to directly contact or be close to the temperature measurement point 8 on the connector 1. The light source module in the photoelectric signal processing device emits light towards the collecting fiber 22, and the excitation fiber 21 collects the light signal to the fluorescent layer 3 at the probe end of the fiber optic sensor. The probe end of the fiber optic sensor integrates a miniature beam splitter, which, through wavelength-selective excitation, separates the signal and radiates fluorescence to form afterglow. The excitation fiber 21 and the afterglow excite the signal processing module in the photoelectric signal processing device, enabling it to collect the fluorescence signal, convert it into an electrical signal, calculate the measured temperature, and finally output the measured temperature through the data output module.

[0044] This invention supports multi-channel synchronous processing, and each ring network cabinet can cover 8-12 temperature measurement points. The fiber optic sensors are arranged in a ring at the elbow joint to realize real-time monitoring of multiple parts such as cable joints, busbars and contacts, with a coverage rate 2.5 times higher than that of traditional infrared point measurement.

[0045] Example 2:

[0046] This embodiment is a further optimization based on Embodiment 1, specifically as follows: Figure 1 As shown, the fluorescent layer 3 is configured as a double layer. The first fluorescent layer is configured as a fluorescent layer containing Y2O3:Eu, and the composition ratio of Y2O3:Eu to phosphor is 1.5:1. The second fluorescent layer is configured as a fluorescent layer containing YPO4:Tb, and the composition ratio of YPO4:Tb to phosphor is 1.5:1. The coating thickness ratio of the first fluorescent layer to the second fluorescent layer is 1.5:1. The second fluorescent layer is disposed between the first fluorescent layer and the encapsulation layer 4.

[0047] This invention employs a multilayer fluorescent material structure, with a fluorescent layer containing Y2O3:Eu and a fluorescent layer containing YPO4:Tb sequentially coated at the end of the fiber optic probe. The main emission peak of the Y2O3:Eu fluorescent layer is 620nm, suitable for temperature measurement scenarios of 0-100℃, while the main emission peak of the YPO4:Tb fluorescent layer is 545nm, suitable for temperature measurement scenarios of 100-200℃. Through wavelength selective excitation and signal separation, the system's temperature measurement range is extended to 0-200℃, and the temperature measurement accuracy is improved to ±0.2℃. Compared with traditional fluorescent fiber optic temperature measurement systems, the temperature measurement accuracy is improved by 80%, effectively meeting the high-precision temperature monitoring requirements of ring main units while reducing the fluorescence signal intensity attenuation rate by 35%, thus improving the lifetime stability of fluorescence under high-temperature conditions.

[0048] The fluorescent layer is prepared by chemical vapor deposition, which ensures tight interlayer bonding and increases the structure's high-temperature resistance and anti-aging properties.

[0049] Example 3:

[0050] This embodiment is a further optimization based on Embodiment 1. Specifically, the light source module is set as a dual-wavelength LED light source, with wavelengths set to 470nm and 532nm respectively, and a pulse modulation frequency of 15kHz. The signal processing module is equipped with a high-speed silicon photodiode and an embedded DSP processor. The high-speed silicon photodiode is positioned facing the excitation fiber 21. The high-speed silicon photodiode receives the fluorescence signal emitted by the excitation fiber 21 and converts the fluorescence signal into an electrical signal. The high-speed silicon photodiode is electrically connected to the embedded DSP processor, and the high-speed silicon photodiode transmits the electrical signal to the embedded DSP processor.

[0051] The overall power consumption of the system is less than 0.8W. It adopts a high-efficiency dual-wavelength LED light source and a high-speed silicon photodiode, which ensures low thermal effect and high stability during long-term operation of the system.

[0052] Example 4:

[0053] This embodiment is a further optimization based on Embodiment 1, specifically as follows: Figure 1 As shown, the fiber optic sensor is covered with a second protective layer 7, which is made of high-temperature resistant ceramic and has an outer diameter of 0.25 mm; the outer surface of the encapsulation layer 4 is provided with titanium oxide; the fiber material 5 is made of Kevlar fiber; and the first protective layer 6 is made of polytetrafluoroethylene propylene.

[0054] The small-diameter fiber optic sensor, through its anti-electromagnetic interference coating, can maintain signal stability under high voltage and strong electromagnetic interference environments, and can be perfectly adapted to confined spaces such as ring main unit cable joints and busbars. At the same time, the invention uses a variety of high-temperature resistant materials, making the system suitable for temperature measurement scenarios of ring main unit cable joints and busbars, ensuring the stability of the equipment in extreme environments.

[0055] Example 5:

[0056] This embodiment is a further optimization based on Embodiment 1, specifically as follows: Figure 1 As shown, a gap is provided between the fluorescent layer 3 and the transmission optical fiber 2. The gap forms an optical cavity, which enhances the temperature measurement sensitivity, buffers thermal expansion stress, and optimizes the collection efficiency of light signals while providing thermal isolation and protection for the fluorescent material.

[0057] Example 6:

[0058] This embodiment is a further optimization based on embodiment 1. Specifically, the data output module is connected to the RS-485 interface, which can remotely monitor the temperature of the ring main unit.

[0059] Example 7:

[0060] This embodiment is a further optimization based on Embodiment 1, specifically as follows: Figures 4 to 6 As shown, the fiber optic sensor has three installation methods, including plug-in installation, simple installation, and embedded installation.

[0061] like Figure 4 As shown, the fiber optic sensor is connected to the connector 1 by an insertion method. By creating a groove inside the connector 1 and filling it with insulating material, the fiber optic sensor is placed in the groove to achieve direct temperature measurement. This insertion method is the main installation method for the fiber optic sensor.

[0062] like Figure 5 As shown, the fiber optic sensor is connected to the connector 1 in a simple installation manner. The fiber optic sensor is placed on the outer surface of the connector 1. The simple installation method requires correction of deviation when monitoring temperature and is suitable for simple scenarios.

[0063] like Figure 6 As shown, the fiber optic sensor is connected to the connector 1 in an embedded installation manner. The connector 1 has a pre-embedded connector 9 inside. The fiber optic sensor is connected to the connector 1 through the pre-embedded connector 9 to realize temperature monitoring of the temperature measuring point 8. The embedded installation method requires improvement of the internal design of the connector 1 to improve the temperature measurement accuracy, but the installation process is relatively complicated.

[0064] Example 8:

[0065] This embodiment provides an application method for a multilayer fluorescent fiber optic temperature measurement system, utilizing any one of the multilayer fluorescent fiber optic temperature measurement systems described in Embodiments 1-7, such as... Figures 1 to 3 As shown, it includes:

[0066] Connect the connector 1 to the inside of the ring main unit via a cable;

[0067] Make the probe end of the fiber optic sensor directly contact or be close to the temperature measuring point 8 on the connector 1;

[0068] The light source module in the photoelectric signal processing device emits an LED light source to the optical fiber end of the optical fiber sensor with a pulse modulation frequency of 15kHz. The light signal is collected by the six collecting optical fibers 22 and sent to the fluorescent layer 3 at the probe end of the optical fiber sensor.

[0069] The probe end of the fiber optic sensor integrates a miniature beam splitter, which separates the signal through wavelength selective excitation, radiates fluorescence to form afterglow, and excites the signal processing module in the photoelectric signal processing device through the excitation fiber 21 and the afterglow.

[0070] The high-speed silicon photodiode in the signal processing module, in conjunction with the low-noise preamplifier circuit, acquires the fluorescence signal and converts it into an electrical signal. The circuit is set to a bandwidth of 120kHz.

[0071] The embedded DSP processor in the signal processing module integrates the adaptive Prony algorithm, and through dynamic baseline correction and multi-band noise filtering, fits the double exponential decay curve of the multilayer fluorescent material to calculate the measured temperature.

[0072] The measured temperature is output through the data output module.

[0073] Example 9:

[0074] This embodiment further optimizes upon embodiment 8. Specifically, it integrates a 64-bit encryption algorithm with frequency hopping anti-interference capabilities, ensuring data security, accuracy, and integrity, and preventing unauthorized operations. The photoelectric signal processing device employs hierarchical access control, allowing system administrators to assign different permissions to operators, restricting unauthorized operations and improving security. The system provides default data and legality checks, reducing repetitive operations and preventing misoperations through user-friendly prompts. It supports three-level intelligent early warning and algorithmic predictive maintenance, issuing real-time warnings, alarms, and over-limit alerts based on preset temperature thresholds. It can provide early warnings of deterioration faults up to two hours in advance, reducing fault location time from hours to minutes, avoiding the difficulty of locating hotspots in traditional inspections, and significantly reducing manual inspection costs. The system is also compatible with the IEC 61850 / Modbus protocol, seamlessly integrating with the digital twin platform to provide highly reliable sensing support for smart distribution networks. This invention supports flexible configuration to meet different user needs, integrates multiple table management and rate management functions, and optimizes the user experience.

[0075] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0076] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multilayer fluorescent fiber optic temperature measurement system, characterized in that, include: Connector (1), which is connected to the inside of the ring main unit via a cable; The fiber optic sensor is placed inside the ring network cabinet. One end of the fiber optic sensor is set as a probe end, and the other end is set as an optical fiber end. The fiber optic sensor is connected to the connector (1) through the probe end. A photoelectric signal processing device is installed inside the ring network cabinet and is connected to the optical fiber end of the optical fiber sensor.

2. The multilayer fluorescent fiber optic temperature measurement system according to claim 1, characterized in that: The probe end of the fiber optic sensor is provided with a fluorescent layer (3) and an encapsulation layer (4). The outer surface of the probe end is coated with the fluorescent layer (3), and the encapsulation layer (4) is sleeved on the fluorescent layer (3).

3. The multilayer fluorescent fiber optic temperature measurement system according to claim 1, characterized in that: The optical fiber sensor includes a transmission optical fiber (2), a fiber material (5), and a first protective layer (6). The transmission optical fiber (2) is wrapped with the fiber material (5), and the first protective layer (6) is sleeved on the fiber material (5). One end of the transmission optical fiber (2) is connected to the probe end.

4. The multilayer fluorescent fiber optic temperature measurement system according to claim 2, characterized in that: The fluorescent layer (3) is configured as a double layer. The first fluorescent layer is configured as a fluorescent layer containing Y2O3:Eu, with a component ratio of Y2O3:Eu to phosphor of 1.5:

1. The second fluorescent layer is configured as a fluorescent layer containing YPO4:Tb, with a component ratio of YPO4:Tb to phosphor of 1.5:

1. The coating thickness ratio of the first fluorescent layer to the second fluorescent layer is [missing information]. 1.5:1, the second fluorescent layer is disposed between the first fluorescent layer and the encapsulation layer (4).

5. The multilayer fluorescent fiber optic temperature measurement system according to claim 3, characterized in that: The transmission optical fiber (2) is composed of one excitation optical fiber (21) and six collection optical fibers (22). The six collection optical fibers (22) are arranged around the excitation optical fiber (21). The excitation optical fiber (21) is located in the center of the six collection optical fibers (22). The optical fibers are arranged at a 25° angle to each other.

6. The multilayer fluorescent fiber optic temperature measurement system according to claim 5, characterized in that: The photoelectric signal processing device includes a light source module, a signal processing module, and a data output module. The light source module is positioned facing the collecting optical fiber (22) and emits an optical signal to the collecting optical fiber (22). The signal processing module is positioned facing the excitation optical fiber (21) and receives the fluorescence signal emitted by the excitation optical fiber (21). The signal processing module is electrically connected to the data output module.

7. The multilayer fluorescent fiber optic temperature measurement system according to claim 6, characterized in that: The light source module is configured as a dual-wavelength LED light source, with wavelengths set to 470nm and 532nm respectively, and a pulse modulation frequency of 15kHz.

8. The multilayer fluorescent fiber optic temperature measurement system according to claim 6, characterized in that: The signal processing module is equipped with a high-speed silicon photodiode and an embedded DSP processor. The high-speed silicon photodiode is positioned facing the excitation fiber (21). The high-speed silicon photodiode receives the fluorescence signal emitted by the excitation fiber (21) and converts the fluorescence signal into an electrical signal. The high-speed silicon photodiode is electrically connected to the embedded DSP processor and transmits the electrical signal to the embedded DSP processor.

9. The multilayer fluorescent fiber optic temperature measurement system according to claim 1, characterized in that: The fiber optic sensor is covered with a second protective layer (7), which is made of high-temperature resistant ceramic and has an outer diameter of 0.25 mm.

10. An application method of a multilayer fluorescent fiber optic temperature measurement system, characterized in that, The multilayer fluorescent fiber optic temperature measurement system according to any one of claims 1-9 comprises: Connect the connector (1) to the inside of the ring main unit via a cable; Make the probe end of the fiber optic sensor directly contact or be close to the temperature measuring point (8) on the connector (1); The light source module in the photoelectric signal processing device emits an LED light source to the fiber end of the fiber optic sensor with a pulse modulation frequency of 15kHz. The light signal is collected by the six collecting optical fibers (22) and sent to the fluorescent layer (3) at the probe end of the fiber optic sensor. The probe end of the fiber optic sensor integrates a miniature beam splitter, which separates the signal through wavelength selective excitation, radiates fluorescence to form afterglow, and excites the signal processing module in the photoelectric signal processing device through the excitation fiber (21) and the afterglow; The high-speed silicon photodiode in the signal processing module, in conjunction with the low-noise preamplifier circuit, acquires the fluorescence signal and converts it into an electrical signal. The circuit is set to a bandwidth of 120kHz. The embedded DSP processor in the signal processing module integrates the adaptive Prony algorithm, and through dynamic baseline correction and multi-band noise filtering, fits the double exponential decay curve of the multilayer fluorescent material to calculate the measured temperature. The measured temperature is output through the data output module.

Images